The Wireless Fidelity (Wi-Fi) Display (WFD) standard has been specified according to needs for transmitting Audio/Video (AV) data while satisfying high quality and low latency. A WFD network to which the WFD standard is applied is a network system proposed by the Wi-Fi Alliance which enables Wi-Fi devices to be connected to each other in a peer-to-peer manner without joining a home network, an office network, or a hotspot network. The WFD devices in the WFD network search for information about each other, for example, capability information, establish a WFD session, and render contents received during the WFD session.
The WFD network includes two types of devices, for example, a source device and a sink device. The source device mirrors data existing on a source screen onto a screen of the sink device. The source device and the sink device exchange a first sequence message with each other and perform device discovery and service discovery. After completion of device discovery and service discovery, an Internet Protocol (IP) address is allocated to the source device and the sink device. Transmission Control Protocol (TCP) connection is established between the source device and the sink device, and then Real Time Streaming Protocol (RTSP) and Real Time Protocol (RTP) stacks for the source device and the sink device are activated.
Capability negotiation between the source device and the sink device is performed through the RTSP, and during capability negotiation, the source device and the sink device exchange M1 through M4 messages. Thereafter, the source device and the sink device exchange WFD session control messages. A data session is established between the source device and the sink device through the RTP.
In the WFD network, a User Datagram Protocol (UDP) is used for data transport. The UDP has no reliability, such that during wireless transmission, some packets may be lost. Since the lost packets are not retransmitted, a loss of data may be noticed by a user. In particular, a data loss related to a text, such as a subtitle, or a Graphic User Interface (GUI) is more noticeable to the user than AV data. Thus, a need exists for a scheme for improving the quality of text and GUI data in the sink device.
To reduce noticeable distortion in the quality of the text and GUI-related data in the sink device, the sink device merges the AV data with the text and GUI-related data, instead of the source device merging the AV data with the text and GUI-related data and transmitting the merged data to the sink device. To merge the text such as a subtitle with the AV data in the sink device, techniques such as Synchronized Multimedia Integration Language (SMIL) or Timed Text Markup Language (TTML) may be used. Likewise, to merge the GUI data with the AV data in the sink device, techniques such as Remote View (RVU), Hyper Text Markup Language (HTML) 5, or Consumer Electronics (CE)-HTML may be used.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.